Let me make sure I have this right; the first death is spiritual (post # 405), the second death is the lake of fire. (post # 417 ) Physical death comes between the first death and the second death but it does not get a number. (post # 427) Even though it is appointed for men to die once, believers die twice and unbelievers die three times. (post # 427)
I did not say that spiritual death was “the first death” in 405. What I said was the only death that is actually numbered is the "second death" in Rev. 20. I think this is to contrast with the "first resurrection" also mentioned in Rev. 20. It you have a part in the first resurrection the second death has no power over you.
Beyond this we know that all men are born dead in trespasses and sin (Eph. 2:1), and must be made alive by the Spirit in order to enjoy fellowship with Christ. We also know that all men (normally) die physically (Heb. 9:27). These deaths are not numbered in the Bible, so perhaps it is confusing to do so.
Something definitely happened when Adam ate the fruit. You say it was spiritual death, God observed, “the man is become as one of us.” I think I will remain on the fence on this one.
What then did God mean when He said, "in the day that you eat of it you shall surely die"?
2 Pet 3:8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.It would be speculation to say that this verse applies here. There are a number of passages that suggest that spiritual death is first. There are also reasons to conclude that physical death is first. If I accept your position, then I must exchange one set of objections for a different set. I believe that there is an explanation that will satisfy all objections, I just don't know what it is, nor do I expect one to come along and end the debate. Scripture is not like that.